A structural element

ABSTRACT

Disclosed is a structural element including of interlocked resilient sheet material components, with each sheet operatively forming a component by being shaped to provide an elongate base with two opposing edges from which a first extension and a second extension respectively extend, with the second extension extending further from the base than the first extension, with the first and second extensions being provided with complimentary interlocking means operatively enabling the extensions of one sheet material component to be interlocked with the extensions of another sheet material component; with the extensions of four sheet components being interlocked, each at a right angle with at least one extension of another one of the sheet components, operatively for four sheet components to provide the structural element with an elongate open-ended core with a plurality of elongate open-ended ribs spaced around the core with each rib being longitudinally aligned with the core.

FIELD OF THE INVENTION

This invention relates to a structural element, such as beams andcolumns.

BACKGROUND TO THE INVENTION

In the structural engineering industry the relative advantages ofconcrete-filled steel tubes (CFST) over a concrete pillar or a steeltube has been well established and proven over many years. Especially inChina and more recently in India, this type of support pillar, column orbeam has been used extensively in the construction of structures such asbridges and buildings.

Concrete-filled steel tubes (CFSTs) have increased point strength, axialstrength, stiffness, torsional strength, shearing strength and bucklingor deformability resistance relative to comparably sized reinforcedconcrete columns. The steel is at its optimal location, as far from thecentroid as possible where it maximizes strength and stiffness whileminimizing weight and material requirements, while it providesconfinement to the concrete infill which cannot move out of its positionuntil the steel sheathing shears to allow it to move outside of theconfinement. In turn, the infill takes up the space inside the tube,thereby resisting or delaying local and global buckling of the tube. Inaddition to their high resistance and stiffness properties, CFSTs caneasily and rapidly be constructed on-site, or pre-made under controlledconditions, thereby eliminating the need for formwork, reinforcement andlabour.

Despite all the clear benefits of CFSTs, global adoption is slow due tosome concerns and shortcomings of this type of tube based pillarstructure that are difficult to overcome, which shortcomings include:

-   -   It is expensive to custom manufacture tubes, so it is expensive        to manufacture a specific tube where specific sizes, shapes,        outer steel skin thicknesses and steel qualities are required;    -   Whenever tubes are custom made according to a specifically        required specification, the quality of the steel binding is very        difficult to control and consistently maintain when welding or        bolts are used;    -   Hollow tubes are not compact and contain a lot of space, so it        is expensive to transport them to site when they are hollow (to        be filled with concrete at site) and very expensive to transport        when they are filled with concrete before the time and then        moved to site;    -   For optimal performance the steel and concrete should bind and        adhere as a single structure, as with concrete and rebar where        the rebar is made to have an uneven surface to facilitate the        binding, but with the flat inner surfaces of tubes this is not        easy to achieve and the concrete tends to separate from the tube        surface over time, thereby potentially changing the        characteristics of the overall structure; and    -   It is very difficult to attach binds that are as strong as the        rest of the CFST to the CSFT that can be used to attach other        structures and objects to the CFST. This is due to the fact        that:        -   the steel and concrete in a CFST are difficult to bind            together, because the inner and outer surfaces of a tube is            typically smooth;        -   it is not easy to attach other members to a CFST because            welding is difficult to inspect and inevitably not as strong            as the rest of the structure; and        -   cutting holes in the tube to insert attachments that bind to            the concrete weakens the structure and does not effectively            distribute the load.

OBJECTIVE OF THE INVENTION

It is an objective of the invention to provide a structural elementwhich at least partly overcomes the abovementioned problems.

SUMMARY OF THE INVENTION

A structural element comprised of a plurality of interlocked resilientsheet material components, with each sheet operatively forming acomponent of the structural element by being shaped to provide anelongate base with two opposing edges from which a first extension and asecond extension respectively extend, with the second extensionextending further from the base than the first extension,

-   -   with the first and second extensions being provided with        complimentary interlocking means operatively enabling the        extensions of one sheet material component to be interlocked        with the extensions of another sheet material component;    -   with the extensions of four sheet components being interlocked,        each at a right angle with at least one extension of another one        of the sheet components,    -   operatively for four sheet components to provide the structural        element with an elongate open-ended core with a plurality of        elongate open-ended ribs spaced around the core with each rib        being longitudinally aligned with the core.

There is further provided for the second extension of a first sheetcomponent to be interlocked with and extending at right angles beyondthe first and second extensions of a second sheet component,

-   -   with the second extension of the second sheet component being        interlocked with and extending at right angles beyond the second        and first extensions of the first sheet component, and with the        first extension of the second sheet component being interlocked        with and extending at right angles beyond the second extension        of the first sheet component and the first extension of a third        sheet component,    -   with the first extension of the third sheet component being        interlocked with and extending at right angles beyond the first        extension of the second sheet component and the second extension        of a fourth sheet component, and with the second extension of        the third sheet component being interlocked with and extending        at right angles beyond the second and first extensions of the        fourth sheet component, and    -   with the second extension of the fourth sheet component being        interlocked with and extending at right angles beyond the second        and first extensions of the third sheet component, and with the        first extension of the fourth sheet component being interlocked        with and extending at right angles beyond the second extension        of the third sheet component and the first extension of a first        sheet component.

There is further provided for the height of each rib to be variable byvarying the lengths of the first and second extensions of the respectivesheet component, and for the width of the rib to be variable by varyingthe length of the bases of opposing sheet components.

In accordance with a further aspect of this invention there is providedeach of the first and the second extensions to terminate in an edgeprovided with a series of spaced apart tabs and slots, with the tabs ofthe first extension being located longitudinally opposite the slots ofthe second extension and with the tabs of the second extension beinglocated longitudinally opposite the slots of the first extension, andwith the tabs of the second extension being longer than the tabs of thefirst extension for the second extension to extend further from the basethan the first extension;

-   -   with the second extension tabs of a first sheet component of the        structural element extending at right angles through and        interlocked with the first extension slots of a second sheet        component of the structural element, and    -   with the second extension tabs of the second sheet component of        the structural element extending at right angles through and        being interlocked with the first extension slots of a third        sheet component of the structural element; and    -   with the second extension tabs of the third sheet component of        the structural element extending at right angles through and        being interlocked with the first extension slots of a fourth        sheet component of the structural element, and    -   with the second extension tabs of the fourth sheet component of        the structural element extending at right angles through and        being interlocked with the first extension slots of the first        sheet component of the structural element;    -   operatively for the four sheet components to provide the        structural element with an elongate open-ended core with a        plurality of elongate open-ended ribs spaced around the core        with each rib being longitudinally aligned with the core, and        with the core being in fluid communication with the interior of        the ribs by the spaces between the spaced apart second extension        tabs extending through the respective first extension slots.

There is further provided for the tabs of the second extension to beabout as long, but no longer than, the width of the base of the sheetmaterial component through which slots it is operatively extended andinterlocked with.

There is still further provided for the core and ribs to be filled witha filler material, preferably a cementitious filler, and more preferablyfor the resilient material to comprise steel, and for the fillermaterial to comprise concrete.

There is also provided for the core to be shaped in the form of acolumn, preferably a right square column, and each rib comprises acolumn, including a right square column or a right rectangular column.

There is still further provided for the interlocking means to includeany one or more of a slot, welding, riveting, gluing, encirclingsecuring members, or retaining members extending through opposing sheetmaterial components.

These and other features of the invention are described in more detailbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention is described by way of exampleonly and with reference to the accompanying drawings in which:

FIG. 1 is a graphical representation of the typical shape of a firstembodiment of a structural element according to the invention, in theform of an X-shaped concrete filled steel column (“XCFC column”);

FIG. 2 is an end view of the structural element of FIG. 1;

FIG. 3A is a graphical representation of the range of interlockinggrooves of the panels forming part of the structural element of FIG. 1where they interlock into each other, with FIG. 3A-1 indicating anexploded view and FIG. 3A-2 an assembled view;

FIG. 3B graphically indicates how the interlocking grooves of FIG. 3Aare used to interlock four panels at a single point;

FIG. 3C graphically indicates how in the structural element of FIG. 1the four panels have four interlocking seams where each of the fourpanels interlocks along at least 3 seams;

FIG. 4 is a graphical representation of seven distinguishing features ofthe structural element shown in FIG. 1;

FIG. 5 indicates graphically by altering the length of the arms, thecharacteristics of the structural element of FIG. 1 can be changed tofit the purpose, with FIG. 5A indicating a balanced cross column, FIG.5B indicating a heavy cross column, and FIG. 5C indicating a light crosscolumn;

FIG. 6 indicates graphically the different bending patterns can be usedat the protruding ends of the components to give differentcharacteristics or structural or aesthetic or interlinking capabilitiesto the structural element of FIG. 1, with FIG. 6A indicating a componentwith square ended ribs, FIG. 6B a component with round ended ribs, andFIG. 6C a component with triangular ended ribs;

FIG. 7 indicates graphically that the concrete in the structural elementof FIG. 1 does not have to be solid, but can have air pockets in them tolower weight or cost;

FIG. 8 indicates graphically that by selectively adding re-enforcingmembers or cable where needed, the structural element of FIG. 1 caneasily be designed and built for purpose;

FIG. 9 indicates graphically that attachment pieces that adheres to therest of the structural element of FIG. 1 can be interwoven with the restof the structure to attach other objects or structures to it, with FIG.9A indicating a plan view, FIG. 9B indicating a side elevation view ofthe element, and FIG. 9C a side elevation view of the element with twoconnectors attached to it;

FIG. 10 indicates graphically the standard sheet metal cutting patternfor the structural element of a second embodiment of a structuralelement according to the invention, in the form of an X-shaped concretefilled steel column (“XCFC column”) which is easy to manage by wideningthe distance between the cutting lines;

FIG. 11 indicates graphically that to form a square ended rib in thestructural element of FIG. 10, the bending pattern requires two bendinglines of 90 degrees each, with FIG. 11A indicating a plan view of thecutting lines on the sheet, FIG. 11B indicating an end view of the bentcomponent, FIG. 11C indicating an exploded end view of four componentsbefore they are interconnected, and FIG. 11D indicating an end view ofthe four panels of FIG. 110 once they have been connected;

FIG. 12 indicates graphically that to form a triangular ended rib in thestructural element of FIG. 10, the bending pattern requires threebending lines, one of 90 degrees in the middle and two of 45 degreeseach, one on either side of the central bending line, with FIG. 12Aindicating a plan view of the cutting lines on the sheet, FIG. 12Bindicating an end view of the bent component, FIG. 12C indicating anexploded end view of four components before they are interconnected, andFIG. 12D indicating an end view of the four panels of FIG. 12C once theyhave been connected;

FIG. 13 is a part sectional view with exploded detail indicating theinteraction between the tabs and slots of the structural element of FIG.10, with FIG. 13A indicating an exploded perspective view of fourcomponents before they are interconnected, FIG. 13B indicating twoopposing components placed in position for joining, and FIG. 13Cindicating all four components joined together; and

FIG. 14 indicates four critical bending sections must be adhered whencutting and bending the sheet in order for the sheet components to fittogether.

DETAILED DESCRIPTION OF THE INVENTION

A first embodiment of a structural element according to the invention,and the principles of securing the element components, are shown inFIGS. 1 to 9. A second embodiment of a structural element according tothe invention is shown in FIGS. 10 to 14.

The first embodiment of the structural element (1), as shown in detailin FIGS. 1 and 2, is comprised of a plurality of interlocked resilientsheet material components (2A-D). Each component is formed from a sheet(3A-D) by being shaped to provide an elongate base (4A-D) with twoopposing edges from which a first extension (5A-1, 5B-1, 5C-1, 5D-1) anda second extension (6A-2, 6B-2, 6C-2, 6D-2) respectively extend, withthe respective second extension (6A-2, 6B-2, 6C-2, 6D-2) extendingfurther from the respective base (4A-D) than the respective firstextension (5A-1, 5B-1, 5C-1, 5D-1).

As shown in FIG. 3 the first (5A-1, 5B-1, 5C-1, 5D-1) and second (6A-2,6B-2, 6C-2, 6D-2) extensions are provided with complimentaryinterlocking means, in this embodiment in the form of slots (7). Asshown in FIG. 3A, this enables the extensions of one sheet materialcomponent (8) to be interlocked with the extensions of another sheetmaterial component (9).

In the structural element the extensions of four sheet components areinterlocked, each at a right angle with at least one extension ofanother one of the sheet components, as shown in more detail in FIG. 3B.The four sheet components (2) thus provide the structural element (1)with an elongate open-ended core (10) with a plurality of elongateopen-ended ribs (11A-D) spaced around the core with each rib (11A-D)being longitudinally aligned with the core (10).

The interlocking of the components (2A-D) thus form the core (10) andlocate the ribs (11A-D) in relation to the core (10). In use, the core(10) and the ribs (11A-D) are filled with a cementitious filler,typically concrete. The components (2A-D) are typically formed fromsteel sheet.

The structural element (1) thus provides an X-shaped concrete filledsteel column (XCFC). The precise shape and pattern of the components(2A-D) can be customised to meet different needs while the steel grade,hardness, tensile strength, yield strength, thickness and otherproperties can be selected based on what sheet metal can be sourced.

FIG. 4 indicates seven distinguishing features of the structural element(1) shown in FIG. 1. These include:

Feature “A”: the cross section consists of 4 interlocking sections whereeach component interlocks with at least 3 interlocking seams;

Feature “B”: the ends can consist of two or more bended sections, andeven a half circle, together completing a 90 degree curve before itjoins the intersection;

Feature “C”: the four ends need not be the same type (one can be a halfcircle and others can for instance be bent at two or more places);

Feature “D”: the four ends can be of different lengths;

Feature “E”: the interlocking section of the components forms a bindingmesh for the concrete and steel to bind together;

Feature “F”: the component slide into place to interlock withoutrequiring the use of screws or welding; and

Feature “G”: reinforcing members and stressed steel support members maybe added to selected areas.

By customising the cutting pattern, the thickness of each of theextensions of the column can be determined on a case by case basis,thereby determining the relative strength of the arms and the structureas a whole.

The length of each of the extensions can similarly be customised,thereby determining the relative strength of the structural element (1)in different directions when applying different forces to it. This isindicated in FIG. 5, in which it is shown how the width and length ofthe four ribs (11A-D) and the core (10) of the structural element (1)can be changed as per the design parameters of the engineer or architectby altering the length of the extensions (12-14).

A balanced cross column structural element (1A) is shown in FIG. 5A,with its extensions (12) being of similar length than the length andwidth of its core (12B).

FIG. 5B shows a heavy cross column structural element (1 B), with itsextensions (13A) being much shorter than the length and width of itscore (13B), and its core (13B) also being larger than the core (12B) ofthe balanced cross column structural element (1A) shown in FIG. 5A.

FIG. 5C shows a light cross column structural element (10), itsextensions (14A) being much longer than the length and width of its core(14B), and its core (14B) being smaller than the cores (12B, 13B) ofstructural elements (1A, 1B) shown in FIGS. 5A and 5B.

As shown in FIG. 6, different bending patterns can be used at theprotruding ends of the components (16-18) to give differentcharacteristics or structural or aesthetic or interlinking capabilitiesto the structural element of FIG. 1. FIG. 6A indicates a component (16)with square ended ribs, FIG. 6B a component (17) with round ended ribs,and FIG. 6C a component (18) with triangular ended ribs.

For each structural element (1) its four components are joined togetherat the central axis of the resulting four-ribbed structural element (1)in such a manner that they interlock with each other, thereby forming auniform and uninterrupted outside steel skin and an interlocked meshedinternal core structure. Once concrete (15) is poured into the steelframe of the structural element (1), the concrete (15) can solidly bindwith the meshed internal steel core of the structural element (1) andits interlocking components, thereby not only securing the bind betweenthe concrete and the steel but also solidifying the interlocked lineswhere the steel components are bound to each other. By positioning thesefour lines where the interlocking between the four components (2A-D)takes place, close to the centre of the structural element (1) whereforces are far less than on the outside thereof where the forces aremaximised, stress on the interlocking lines are further minimised whilethe need for welding and bolts are negated.

For increased strength, extra re-enforcing members, includingpre-stressed and post-stressed steel cables and rods as well asreinforcing ties can be added to the inner core of any or all of theextensions in order to change the characteristics of structural element(1) when applying different forces to it. This enables the engineer,designer or architect to use the same basic design and manufacturingprocess to create structural elements in the form of pillars, columns,plinths and beams with characteristics designed to handle the specificaxial load, point load, distributed load, torsional and shear forces itis designed to withstand for the specific application it is to be usedfor.

As shown in FIG. 7 the structural element (1) that is filled withconcrete (15) not have to be solid, but can have air pockets (19-20)that are located in or extend through the core (10) and/or ribs (11) inthem to lower weight or cost.

As shown in FIG. 8, in order to strengthen the outer section of anextension of the structural element (1) where the forces are greatestonce load is applied to it, a 90 degree bent steel V-section (21) canfor instance be added to the inside of the outer sections of an theextension (22) where the concrete, once added, will push it against theinside (23) of the steel skin of the extension (22).

Similarly, and also shown in FIG. 8, when used as a beam, one or morehollow tubes (24) can be inserted into the internal cavity of the bottomextension (25) of such a beam, or the bottom of the core (26), throughwhich post stressing cables can be strung and tensioned to provide apost stressed beam section. A steel V-section can even be added to thetop one or two extensions of a beam to strengthen those sections frombuckling while post-stressed cables are added to the bottom one or twoextensions, as shown in FIG. 8.

As shown in FIG. 9, to attach binds to the structural element (1) thatadhere to it and can be used to attach other structures or objects tothe structural element (1), one or more attachment bands or attachmentbinds (27) can be interwoven with the core along with one or more of thefour extensions of the structural element (1). By doing this, theattachment band or attachment bind (27) does not weaken the structure inany way, while it can be interlocked with the steel structure and boundto the concrete using rough edges where it is interwoven with theconcrete, making the bind adhere to the structural element (1) withoutweakening it or the attachment piece itself.

Common fabrication tools such as plasma or laser cutters and bench pressbenders can be used to fabricate the structural element (1), therebymaking the fabrication process easy and the very cost effective, evenwhen customising the standard cutting patterns that can be issued forthe invention.

By cost effectively giving the engineer, designer or architect thefreedom to select column width and thickness, steel grade, properties,strength, thickness, hardness and corrosive properties, and then makingit easy to adapt the standard designs to suit the customisedrequirement, the engineer, designer or architect is given the freedom todesign the concrete filled steel column structural element (1) accordingto the needs of the overall design and not based on what tube sizes,shapes, wall thicknesses and steel grades are available in the market atthe time.

The second embodiment of a structural element (30) according to theinvention is shown in FIGS. 10-14. In this instance the structuralelement (30) is comprised of four sheet components, each of whichincludes first (31) and the second (32) extensions that extend from abase (33). Each of the first (31) and the second (32) extensionsterminate in an edge that is provided with a series of spaced apart tabs(34, 35) and slots (36, 37).

The tabs (34) of each first extension (31) are located longitudinallyopposite the slots (37) of its second extension (32) and the tabs (35)of its second extension (32) are located longitudinally opposite theslots (36) of its first extension (31). The tabs (35) of the secondextension (32) are longer than the tabs (34) of the first extension(31), which enables in respect of each sheet component (30) the secondextension (32) to extend further from the base (33) than its firstextension (31).

As shown in FIGS. 10 and 11 the bases (33) of the components may havecustom shapes, for example square (33A) or triangular (33B). Othershapes, for example round, are also possible.

To manufacture the sheet component common fabrication tools such asplasma or laser cutters and bench press benders can be used to fabricatethe structural element (30), thereby making the fabrication process easyand the very cost effective, even when customising the standard cuttingpatterns that can be issued for the invention.

By cost effectively giving the engineer, designer or architect thefreedom to select column width and thickness, steel grade, properties,strength, thickness, hardness and corrosive properties, and then makingit easy to adapt the standard designs to suit the customisedrequirement, the engineer, designer or architect is given the freedom todesign the concrete filled steel column structural element (30)according to the needs of the overall design and not based on what tubesizes, shapes, wall thicknesses and steel grades are available in themarket at the time.

Each elongate component (30A, 30B) is then bent on the bend linesindicated on the sheet, in FIGS. 10A and 11A respectively, to transformthe flat cut sheets (38, 39) into component panels (40A, 40B), as shownin FIGS. 10B and 11B. The components panels (40A, 40B) are then alignedas shown in FIGS. 10C and 11C respectively before being interlocked intothe assembled structural elements (41A, 41B) as shown in FIGS. 10D and11D.

In this second embodiment of the structural element (30) the componentsare cut from metal sheet (42), along cut lines as for example indicatedin FIG. 12. The sheet (42) in FIG. 12 has a repeating pattern of fourcomponents, with a first set of four components (43A-D) followed by asecond set of four components (44), of which only the first (44A) isshown in FIG. 12. The flat panels shown in FIGS. 10A and 11A are formedby cutting it sheet along the cut lines, similar to that shown in FIG.12.

The assembly mentioned above with reference to FIGS. 10C-D and 11C-D aredescribed in more detail below with reference to FIGS. 13A to 13C, inwhich the square ended components of FIG. 10 are used. In this assembly:

-   -   the second extension tabs (35-1) of the first sheet component        (40A-1) extend at right angles through and are interlocked with        the first extension slots (34-2) of the second sheet component        (40A-2);    -   the second extension tabs (35-2) of the second sheet component        (40A-2) extend at right angles through and are interlocked with        the first extension slots (34-3) of the third sheet component        (40A-3);    -   the second extension tabs (35-3) of the third sheet component        (40A-3) extend at right angles through and are interlocked with        the first extension slots (34-4) of the fourth sheet component        (40A-4);    -   and the second extension tabs (35-4) of the fourth sheet        component (40A-4) extend at right angles through and are        interlocked with the first extension slots (34-1) of the first        sheet component (40A-1).

Thus the four sheet components provide the structural element (41A) withan elongate open-ended core (45) with a plurality of elongate open-endedribs (40A-1 to 40A-4) spaced around the core (45) with each rib (40A-1to 40A-4) being longitudinally aligned with the core (45). The core (45)is in fluid communication with the interior of the ribs (40A-1 to 40A-4)through the second extension slots (37) between the spaced apart secondextension tabs (35) that in assembly extend through the respective firstextension slots (36).

The spaced apart second extension tabs (35), which are the longer of thetabs (34, 35), extend across the interior of the ribs (40A-1 to 40A-4),in each case adjacent the rib of which the specific second extensiontabs (35) form part. For example, the second extension tabs (35-1) ofthe first sheet component (40A-1) extend across the interior of the ribforming part of the second sheet component (40A-2), and so on.

With the second extension tabs (35) of each sheet component being spacedapart the interior of the ribs are not isolated form the core (45).Concrete filled into the core also fills the ribs and vice versa. Thisallows concrete poured into the structural element (41A) to bind theribs (40A-1 to 40A-4) and the core (45) together, significantlyimproving its strength without requiring additional reinforcing membersthat extend into the concrete.

A further feature is shown in FIGS. 10 to 14, and this relates to nibs(50, 52, 54) and cuts (51, 53, 55) on the tabs (34, 35). As shown indetail in FIG. 14, each first extension tab (34) is provided with a nib(50) proximate its edge which projects partly over the adjacent slot(36), and a complimentary sized cut (51) proximate the base of theadjoining slot (36). Each second extension tab (35) is provided with anib (52) and a cut (53) set proximate its edge and another nib (54) anda cut (55) set adjacent the base of an adjoining slot (37).

In assembly, the nibs (50, 52, 54) and cuts (51, 53, 55) of therespective tabs (34, 35) and slots (36, 37) engage with opposing cutsand nibs, the further secure the respective bent sheet componentstogether.

FIG. 14 indicates four critical bending sections must be adhered whencutting and bending the sheet in order for the sheet components to fittogether. These include the width (46) of the first extension, the width(48) of the second extension, and the width between the inner nib (52)and outer cut (55) on the second extension tabs (35) which must be equalto the width of the base (47).

This structural elements (1, 30) according to the invention therebyovercome the problems or concerns associated with CFSTs:

-   -   1) Unlike with a CFST, in this invention the steel binds to the        concrete, enabling the composite structure to adhere and act as        a single structure;    -   2) Pre-cut sheet metal plate components can be packed tightly        for improved density to lower transportation cost to site where        it can be assembled and the concrete can be added;    -   3) Easy and cost effective custom design of a concrete filled        steel column structural element (1, 30) is made possible with        the structural element (1, 30) of the invention;    -   4) Binding of the four components with each other and with the        concrete happens as a result of solidifying a steel interlocking        mechanism with concrete, so bolts and welding and other forms of        costly and risky binding are not required;    -   5) An attachment piece to attach other objects or structures to        the structural element (1, 30) and that is as strong as the        structural element (1, 30) while binding and adhering to both        the steel and concrete parts of the structural element (1, 30)        without weakening either the attachment piece or the structural        element (1, 30) is made possible by interweaving the attachment        piece to the concrete and steel core and interlocking slots.

Although steel and concrete is used in the preferred embodiments of thestructural element (1, 30) of the invention, the steel can be replacedby a different solid sheet based material such as plastics, plasticcompounds, titanium, aluminium and others, and even be moulded into thedescribed shape as opposed to being cut and bent, if required.Similarly, the concrete can be replaced by another solidifying compoundsuch as a glue, epoxy, foam, plastic, nylon and others.

The structural element (1, 30) of the invention can be used in theconstruction industry in any suitable structure where high strengthpillars, beams, supports, columns or plinths are required such as forbridges, high rise buildings, warehouses and other buildings, highlighting supports (streetlights), aerial guideways and causeways(transportation tracks and power cables), towers and others. As has beenproven by studies done on CFSTs, the combined properties of steel andconcrete makes the overall structure much stronger than either aconcrete or steel column would be on its own, and by enabling low costmanufacturing and the freedom to customise, engineers, designers andarchitects are given a range of cost effective tools to optimisestructure design. By pre-manufacturing the columns to specification andassembling on site, thereby doing away with on-site formwork,inspections and curing time, construction cost and time can be saved.

In construction where columns, beams or pillars are required, thestructural element (1, 30) of the invention gives engineers, designersand architects and builders the benefits of much improved strength, easeof customisation, lower cost manufacturing, lower cost construction andreduced construction time.

Where required, to further facilitate bonding of the concrete with thesteel sheet, the sheet from which each component of the structuralelement (1, 30) is formed can be scoured or roughened up before it iscut.

The structural element (1, 30) of the invention can be used to easilyand cost effectively custom design and manufacture a super strongconcrete filled steel beam or pillar to the specifications that isrequired for the specific project such as the construction of a multistorey building.

It will be appreciated that the embodiments described above are given byway of example only and are not intended to limit the scope of theinvention. Modifications to these embodiments are possible withoutdeparting from the essence of the invention.

1-10. (canceled)
 11. A structural element, comprising: a plurality ofinterlocked resilient sheet material components, each of the pluralityof interlocked resilient sheet material components operatively forming acomponent of the structural element by being shaped to provide anelongate base with two opposing edges from which a first extension and asecond extension respectively extend, with the second extensionextending further from the elongate base than the first extension;wherein the first and second extensions are provided with complimentaryinterlocking means operatively enabling the extensions of one of theplurality of interlocked resilient sheet material components to beinterlocked with the extensions of another sheet material component ofthe plurality of interlocked resilient sheet material components;wherein the first and second extensions of four sheet components of theplurality of interlocked resilient sheet material components beinginterlocked, each at a right angle with at least one extension ofanother one of the plurality of interlocked resilient sheet materialcomponents; wherein operatively for four sheet components of theplurality of interlocked resilient sheet material components to providethe structural element with an elongate open-ended core with a pluralityof elongate open-ended ribs spaced around the elongate open-ended corewith each of the plurality of elongate open-ended ribs beinglongitudinally aligned with the elongate open-ended core.
 12. Thestructural element of claim 11 wherein: the second extension of a firstsheet component of the plurality of interlocked resilient sheet materialcomponents is interlocked with and extending at right angles beyond thefirst and second extensions of a second sheet component of the pluralityof interlocked resilient sheet material components; the second extensionof the second sheet component being interlocked with and extending atright angles beyond the second and first extensions of the first sheetcomponent, and with the first extension of the second sheet componentbeing interlocked with and extending at right angles beyond the secondextension of the first sheet component and the first extension of athird sheet component of the plurality of interlocked resilient sheetmaterial components; the first extension of the third sheet componentbeing interlocked with and extending at right angles beyond the firstextension of the second sheet component and the second extension of afourth sheet component of the plurality of interlocked resilient sheetmaterial components, and with the second extension of the third sheetcomponent being interlocked with and extending at right angles beyondthe second and first extensions of the fourth sheet component; and thesecond extension of the fourth sheet component being interlocked withand extending at right angles beyond the second and first extensions ofthe third sheet component, and with the first extension of the fourthsheet component being interlocked with and extending at right anglesbeyond the second extension of the third sheet component and the firstextension of a first sheet component.
 13. The structural element ofclaim 12 wherein: each of the plurality of elongate open-ended ribs hasa height that is variable by varying lengths of the first and secondextensions of the respective sheet component of the plurality ofinterlocked resilient sheet material components; and the elongateopen-ended rib has a width that is variable by varying a length of theelongate bases of opposing sheet components of the plurality ofinterlocked resilient sheet material components.
 14. The structuralelement of claim 11 wherein: each of the first and the second extensionsterminates in an edge provided with a series of spaced apart tabs andslots, with the tabs of the first extension being located longitudinallyopposite the slots of the second extension and with the tabs of thesecond extension being located longitudinally opposite the slots of thefirst extension, and with the tabs of the second extension being longerthan the tabs of the first extension for the second extension to extendfurther from the elongate base than the first extension; the secondextension tabs of a first sheet component of the structural elementextending at right angles through and interlocked with the firstextension slots of a second sheet component of the structural element;the second extension tabs of the second sheet component of thestructural element extending at right angles through and interlockedwith the first extension slots of a third sheet component of thestructural element; the second extension tabs of the third sheetcomponent of the structural element extending at right angles throughand interlocked with the first extension slots of a fourth sheetcomponent of the structural element; the second extension tabs of thefourth sheet component of the structural element extending at rightangles through and interlocked with the first extension slots of thefirst sheet component of the structural element; and operatively for thefour sheet components to provide the structural element with an elongateopen-ended core with a plurality of elongate open-ended ribs spacedaround the elongate open-ended core with each rib being longitudinallyaligned with the elongate open-ended core, and with the elongateopen-ended core being in fluid communication with the interior of theribs by the spaces between the spaced apart second extension tabsextending through the respective first extension slots.
 15. Thestructural element of claim 14 wherein the extension tabs of the secondextension is about as long but no longer than a width of the elongatebase of the sheet material component through which slots it isoperatively extended and interlocked with.
 16. The structural element ofclaim 11 wherein the elongate open-ended core and the plurality ofelongate open-ended ribs are filled with a filler material.
 17. Thestructural element of claim 16 wherein: the plurality of interlockedresilient sheet material components include a resilient materialincluding steel; and the filler material includes concrete.
 18. Thestructural element of claim 11 wherein the elongate open-ended core andthe plurality of elongate open-ended ribs are filled with a cementitiousfiller.
 19. The structural element of claim 11 wherein the elongateopen-ended core is shaped in the form of a column, each of the pluralityof elongate open-ended ribs includes a column including a right squarecolumn or a right rectangular column.
 20. The structural element ofclaim 19 wherein the column includes a right square column.
 21. Thestructural element of claim 11 wherein the interlocking means includesone or more of a slot, welding, riveting, gluing, encircling securingmembers, or retaining members extending through opposing sheet materialcomponents of the plurality of interlocked resilient sheet materialcomponents.